This invention relates to dental instruments used to facilitate cavity repairs.
In dentistry it is a common practice to repair cavities by drilling out the decayed material to form a cavity preparation, and filling the cavity preparation with some type of restoration material. A very common cavity found on the tooth surface is the facial or lingual cavity in the gingival or subgingival area of the crown of the tooth. This type of cavity is common due to the shape of the marginal gingiva next to the tooth surface, which has a natural tendency to collect food and plaque.
In order to place either an amalgam or composite restoration material in this area, the gingiva must be retracted from the cavity region for a sufficiently long time period to keep the cavity preparation dry and free from blood and saliva so as not to contaminate the filling material while it is being emplaced. In today's practice this required retraction is usually accomplished by the use of a flat bladed spatula type instrument. Due to the shape of the spatula type instrument, the marginal gingiva is usually irritated, lacerated or torn during retraction, which does not guarantee that the cavity preparation will be kept dry and free from fluid contamination and which also leads to deterioration of the gingival tissue, both of which are undesirable.
Another instrument used in present practice to retract the gingiva is the rubber dam clamp, which is time consuming to install, awkward to use, and typically retracts only that portion of the gingiva positioned centrally of the root surface of the tooth at the gingival level.